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Mammal Species Richness (mammal + species_richness)
Selected AbstractsElevational gradients of small mammal diversity on the northern slopes of Mt. Qilian, ChinaGLOBAL ECOLOGY, Issue 6 2003Jun Sheng Li ABSTRACT Aim, Small mammal species richness and relative abundance vary along elevational gradients, but there are different patterns that exist. This study reports the patterns of distribution and abundance of small mammals along the broader elevational gradient of Mt. Qilian range. Location, The study was conducted in the Mt. Qilian range, north-western China, from June to August 2001. Methods, Removal trapping was conducted using a standardized technique at 7 sites ranging between 1600 and 3900 m elevation within three transects. Correlation, regression and graphical analyses were used to evaluate the diversity patterns along this elevational gradient. Results, ,In total, 586 individuals representing 18 nonvolant small mammal species were collected during 20 160 trap nights. Species composition was different among the three transects with 6 (33%) of the species found only within one transect. Elevational distribution and relative abundance of small rodents showed substantial spatial variation, with only 2 species showing nonsignificant capture frequencies across elevations. Despite these variations, some general patterns of elevational distribution emerged: humped-shape relationships between species diversity and elevation were noted in all three transects with diversity peaks at middle elevations. In addition, relative abundance was negatively correlated with elevation. Conclusions, Results indicate that maximum richness and diversity of nonvolant small mammals occurred at mid-elevations where several types of plants reached their maximum diversity and primary productivity, and where rainfall and humidity reached a maximum. It is demonstrated that the mid-elevation bulge is a general feature of at least a large portion of the biota on the Mt. Qilian range. [source] Factors determining mammal species richness on habitat islands and isolates: habitat diversity, disturbance, species interactions and guild assembly rulesGLOBAL ECOLOGY, Issue 1 2000Barry J. Fox Abstract 1For over three decades the equilibrium theory of island biogeography has galvanized studies in ecological biogeography. Studies of oceanic islands and of natural habitat islands share some similarities to continental studies, particularly in developed regions where habitat fragmentation results from many land uses. Increasingly, remnant habitat is in the form of isolates created by the clearing and destruction of natural areas. Future evolution of a theory to predict patterns of species abundance may well come from the application of island biogeography to habitat fragments or isolates. 2In this paper we consider four factors other than area and isolation that influence the number and type of mammal species coexisting in one place: habitat diversity, habitat disturbance, species interactions and guild assembly rules. In all examples our data derive from mainland habitat, fragmented to differing degrees, with different levels of isolation. 3Habitat diversity is seen to be a good predictor of species richness. Increased levels of disturbance produce a relatively greater decrease in species richness on smaller than on larger isolates. Species interactions in the recolonization of highly disturbed sites, such as regenerating mined sites, is analogous to island colonization. Species replacement sequences in secondary successions indicate not just how many, but which species are included. Lastly, the complement of species established on islands, or in insular habitats, may be governed by guild assembly rules. These contributions may assist in taking a renewed theory into the new millennium. [source] Climate-based models of spatial patterns of species richness in Egypt's butterfly and mammal faunaJOURNAL OF BIOGEOGRAPHY, Issue 11 2009Tim Newbold Abstract Aim, Identifying areas of high species richness is an important goal of conservation biogeography. In this study we compared alternative methods for generating climate-based estimates of spatial patterns of butterfly and mammal species richness. Location, Egypt. Methods, Data on the occurrence of butterflies and mammals in Egypt were taken from an electronic database compiled from museum records and the literature. Using Maxent, species distribution models were built with these data and with variables describing climate and habitat. Species richness predictions were made by summing distribution models for individual species and by modelling observed species richness directly using the same environmental variables. Results, Estimates of species richness from both methods correlated positively with each other and with observed species richness. Protected areas had higher species richness (both predicted and actual) than unprotected areas. Main conclusions, Our results suggest that climate-based models of species richness could provide a rapid method for selecting potential areas for protection and thus have important implications for biodiversity conservation. [source] Mammal community structure in relation to disturbance and resource gradients in southern AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 1 2009Märtha Wallgren Abstract The arrangements of mammals differ along environmental gradients, such as of disturbance and resources. We examined how mammal community composition in the Kalahari, Botswana, varied in relation to disturbance and resource gradients. We predicted that livestock-keeping villages are disturbances and pans are resources for wildlife, that the responses of mammals to disturbance and resources depend on their functional types and that increased disturbance over time has reduced the numbers and distributions of wildlife. The methods involved road-side counts of mammals >0.2 kg and trapping of small mammals, <0.2 kg. The disturbance gradient was more important than the resource gradient for explaining the distribution of mammals >0.2 kg. Communities in low disturbance-high resource areas were most diverse regarding species and functional types. Small mammal species richness and abundances were unaffected by villages, but increased with distance from pans. Villages were particularly deterring to large wild herbivores, functionally similar to livestock. Most large wild herbivores had decreased since 1975,1983. We conclude that large and medium-sized mammals are highly affected by large-scale disturbance gradients, while small mammals are most dependent on small-scale variation in resources, probably shelter and food. Increased disturbance over time leads to decreasing ranges and numbers of the large wild herbivores. Résumé Les associations de mammifères diffèrent selon des gradients environnementaux tels que ceux des perturbations et des ressources. Nous avons examiné comment la composition de la communauté de mammifères variait dans le Kalahari, au Botswana, en fonction des gradients de perturbations et de ressources. Nous avions prédit que les villages qui gardent du bétail sont des perturbations, et les pans des ressources pour la faune sauvage, que les réponses des mammifères à ces deux facteurs dépendaient de leur type de fonctionnement, et que les perturbations croissant avec le temps avaient réduit l'abondance et la distribution de la faune sauvage. Les méthodes employées comprenaient les comptages le long de la route de tous les mammifères de plus de 0,2 kg et le piégeage des petits mammifères de moins de 0,2 kg. Le gradient de perturbation était plus important que celui des ressources pour expliquer la distribution des mammifères >0,2 kg. Les communautés vivant dans les zones de faibles perturbations et d'abondantes ressources étaient plus diverses au point de vue du nombre d'espèces et de types fonctionnels. La richesse en espèces de petits mammifères et leur abondance n'étaient pas affectées par les villages mais augmentaient avec la distance par rapport au pan. Les villages étaient particulièrement dissuasifs pour les grands herbivores sauvages qui étaient, fonctionnellement, semblables au bétail. La plupart des grands herbivores sauvages ont diminué depuis 1975,1983. Nous concluons que les herbivores grands et moyens sont fort affectés par les gradients de perturbations à grande échelle alors que les petits mammifères sont surtout dépendants des variations à petite échelle des ressources, probablement les abris et la nourriture. Les perturbations croissant avec le temps entraînent une réduction des domaines vitaux et du nombre des grands herbivores sauvages. [source] | ||||||||||